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    <title>VietOCR.NET - .NET GUI Frontend for Tesseract OCR</title>
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        <h2 align="center">
            VietOCR.NET</h2>
        <h3>
            DESCRIPTION</h3>
        <p>
            <a href="http://sourceforge.net/project/showfiles.php?group_id=153105">VietOCR.NET</a>
            is a .NET GUI frontend for <a href="http://code.google.com/p/tesseract-ocr/">Tesseract
                OCR engine</a>, providing character recognition support for common image formats,
            and multi-page images. The program has postprocessing which helps correct errors
            regularly encountered in the OCR process, boosting the accuracy rate on the result.
            The program can also function as a console application, executing from the command
            line.</p>
        <p>
            Batch processing is now supported. The program monitors a watch folder for new image
            files, automatically processes them through the OCR engine, and outputs recognition
            results to an output folder.</p>
        <h3>
            SYSTEM REQUIREMENTS</h3>
        <p>
            <a href="http://www.microsoft.com/downloads/details.aspx?familyid=5B2C0358-915B-4EB5-9B1D-10E506DA9D0F&displaylang=en">
                Microsoft .NET Framework 2.0 Redistributable</a>.</p>
        <p>
            If you encounter a FileLoadException with message &quot;<i>Could not load file or assembly
                &#39;tesseract, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null&#39; or one
                of its dependencies. This application has failed to start because the application
                configuration is incorrect. Reinstalling the application may fix this problem. (Exception
                from HRESULT: 0x800736B1)</i>&quot; while running VietOCR.NET, please install
            Microsoft Visual C++ 2008 SP1 Redistributable Package (<a href="http://www.microsoft.com/downloads/details.aspx?FamilyID=a5c84275-3b97-4ab7-a40d-3802b2af5fc2&displaylang=en">x86</a>,
            <a href="http://www.microsoft.com/downloads/details.aspx?familyid=BA9257CA-337F-4B40-8C14-157CFDFFEE4E&displaylang=en">
                x64</a>).</p>
        <h3>
            INSTALLATION</h3>
        <p>
            If you do not have authority to install under <tt>C:\Program Files</tt> folder,
            you can specify another folder in Install Installation Folder dialog.</p>
        <p>
            Scanning support is provided via the Windows Image Acquisition Library v2.0, which
            requires Windows XP Service Pack 1 (SP1) or later; the library is included in Vista and 7. To install the WIA Library, copy
            the <tt>wiaaut.dll</tt> file to your <tt>System32</tt> directory (usually located
            at <tt>C:\Windows\System32</tt>) and run from the command line:</p>
        <blockquote>
            <p>
                <tt>regsvr32 C:\Windows\System32\wiaaut.dll</tt></p>
        </blockquote>
        <p>
            PDF support is possible via <a href="http://sourceforge.net/projects/ghostscript/">GPL
                Ghostscript</a>. After installation of the library, please ensure the dynamic
            load library <tt>gsdll32.dll</tt> is in the search path by setting the <tt>Path</tt>
            environment variable, which is accessible through Windows&#39; Control Panel &gt;
            System &gt; Advanced tab &gt; Environment Variables. For instance, append the following
            to <tt>Path</tt> variable value for GS version 9.10:</p>
        <blockquote>
            <p>
                <tt>;C:\Program Files\gs\gs9.10\bin</tt></p>
        </blockquote>
        <p>
            Spellcheck functionality is available through Hunspell, whose <a href="http://wiki.services.openoffice.org/wiki/Dictionaries">
                dictionary</a> files (<tt>.aff</tt>, <tt>.dic</tt>) should be placed in <tt>dict</tt>
            folder of VietOCR.</p>
        <h3>
            INSTRUCTIONS</h3>
        <p>
            <a href="http://code.google.com/p/tesseract-ocr/downloads/list">Language data packs</a>
            for Tesseract should be decompressed into <tt>tesseract</tt> installation folder;
            the data files, whose names start with ISO639-3 codes, will be placed in the <tt>tessdata</tt>
            subdirectory. VietOCR also provides support for downloading and installing selected
            language packs via <em>Download Language Data</em> menu item. Depending on the location
            of the <tt>tessdata</tt> folder, you may be required to run the program as admin
            to be able to install the downloaded data into the folder if it is inside a system
            folder, such as in <tt>C:\Program Files</tt>.</p>
        <p>
            The Vietnamese language data were generated for Times New Roman, Arial, Verdana,
            and Courier New fonts. Therefore, the recognition would have better success rate
            for images having similar font glyphs. OCRing images that have font glyphs look
            different from the supported fonts generally will require <a href="http://code.google.com/p/tesseract-ocr/wiki/TrainingTesseract">
                training</a> Tesseract to create another language data pack specifically for
            those typefaces. Language data for some VNI and TCVN3 (ABC) fonts have also been
            bundled in latest versions.</p>
        <p>
            Images to be OCRed should be scanned at resolution from at least 200 DPI (dot per
            inch) to 400 DPI in monochrome (black&amp;white) or grayscale. Scanning at higher
            resolutions will not necessarily result in better recognition accuracy, which currently
            can be higher than 97% for Vietnamese, and the next release of Tesseract may improve
            it even further. Even so, the actual rates still depend greatly on the quality of
            the scanned image. The typical settings for scanning are 300 DPI and 1 bpp (bit
            per pixel) black&amp;white or 8 bpp grayscale uncompressed TIFF or PNG format.</p>
        <p>
            The <em>Screenshot Mode</em> offers better recognition rates for low-resolution
            images, such as screen prints, by rescaling them to 300 DPI.</p>
        <p>
            In addition to the built-in text postprocessing algorithm, you can add your own
            custom text replacement scheme via a text file named <tt>x.DangAmbigs.txt</tt>,
            where x is the ISO639-3 language code. The UTF-8-encoded file should contain equal
            sign-delimited <tt>oldValue=newValue</tt> pairs.</p>
        <p>
            Some built-in tools are provided to merge several images or PDF files into a single
            one for convenient OCR operations, or to split a PDF file into smaller ones if it
            is too large, which can cause out-of-memory exceptions.</p>
        <h3>
            POSTPROCESSING</h3>
        <p>
            The recognition errors can generally be classified into three categories. Many of
            the errors are related to the letter cases — for example: hOa, nhắC — which can
            be easily corrected by popular Unicode text editors. Many other errors are a result
            of the OCR process, such as missing diacritical marks, wrong letters with similar
            shape, etc. — huu – hưu, mang – marg, h0a – hoa, la – 1a, uhìu - nhìn. These can
            also be easily fixed by spell checker programs. The built-in Postprocessing function
            can help correct many of the aforementioned errors.</p>
        <p>
            The last category of errors is the most difficult to detect because they are semantic
            errors, which means that the words are valid entries in the dictionary but are wrong
            in the context — e.g., tinh – tình, vân – vấn. These errors require the editor to
            read though and manually correct them according to the original image.</p>
        <p>
            Following are instructions on how to correct the first two categories of OCR errors
            using the built-in functionality:</p>
        <ol style='margin-top: 0in' start="1" type="1">
            <li>Group lines. The lines need to be grouped to the paragraph they belong, as being
                OCRed, each line becomes a separate 1-line paragraph. Use <i>Remove Line Breaks</i>
                function under <i>Format</i> menu. Note that this operation may not be needed for
                poems.</li>
            <li>Select <i>Change Case</i>, also under <i>Format</i> menu, and choose <i>Sentence
                case</i> to correct most of the letter case errors. Locate and fix the rest of remaining
                letter case errors.</li>
            <li>Correct the misspelled errors using the integrated <i>Spell Check</i>.</li>
        </ol>
        <p>
            Through the above process, most of common errors can be eliminated. The remaining,
            semantic errors are few, but it requires a human editor to read though and make
            necessary edits to make the document like the original scanned document.</p>
        <p>
            If there is any questions, please post in <a href="http://sourceforge.net/projects/vietocr/forums">
                VietOCR Forum</a>.</p>
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